we have breaking news tonight on that widening e-mail scandal rocking washington and the world. a scandal that led to the resignation of cia chief david petraeus. late this evening, abc news learned that general john allen, the top u.s. commander in afghanistan, is being investigated for possibly inappropriate e-mail communications with one of the women linked to the petraeus scandal. it's the latest bombshell. kelly is a family friend of petraeus and notified the fbi she was receiving threatening e-mails. martha raddatz has the story. >> reporter: when general david petraeus granted paula broadwell exclusive and extraordinary access to pep his biography, he likely never imagined it would lead to his downfall. but tonight, his reputation is sullied. the fbi is under scrutiny, and agents have descended on broadwell's home to gather more material, material broadwell is now willingly providing them in this increasingly strange scandal. the affair first came to light this summer as part of an fbi investigation prompted by a complaint from this woman, jill kelly. a private citizen an